Many biological actions, for instance, response to certain stimuli and natural biological processes, are controlled by factors, such as cytokines. Many cytokines act through receptors by engaging the receptor and producing an intra-cellular response.
For example, tumor necrosis factors (TNF) alpha and beta are cytokines which act through TNF receptors to regulate numerous biological processes, including protection against infection and induction of shock and inflammatory disease. The TNF molecules belong to the “TNF-ligand” superfamily, and act together with their receptors or counter-ligands, the “TNF-receptor” superfamily. So far, at least eighteen members of the TNF ligand superfamily have been identified and at least nineteen members of the TNF-receptor superfamily have been characterized (See, e.g., Locksley et el., Cell (2001) 104:487-501).
Among the ligands there are included TNF-α, lymphotoxin-α (LT-α, also known as TNF-β), LT-β (found in complex heterotrimer LT-α2-β), FasL, CD40L, CD27L, CD30L, 4-1BBL, OX40L and nerve growth factor (NGF). The superfamily of TNF receptors includes the p55TNF receptor, p75TNF receptor, TNF receptor-related protein, FAS antigen or APO-1, CD40, CD27, CD30, 4-1BB, OX40, low affinity p75 and NGF-receptor (Meager, A., Biologicals, 22:291-295 (1994)).
Many members of the TNF-ligand superfamily are expressed by activated T-cells, implying that they are necessary for T-cell interactions with other cell types which underlie cell ontogeny and functions. (Meager, A., supra).
Considerable insight into the essential functions of several members of the TNF receptor family has been gained from the identification and creation of mutants that abolish the expression of these proteins. For example, naturally occurring mutations in the FAS antigen and its ligand cause lymphoproliferative disease (Watanabe-Fukunaga, R., et al., Nature 356:314 (1992)), perhaps reflecting a failure of programmed cell death. Mutations of the CD40 ligand cause an X-linked immunodeficiency state characterized by high levels of immunoglobulin M and low levels of immunoglobulin G in plasma, indicating faulty T-cell-dependent B-cell activation (Allen, R. C. et al., Science 259:990 (1993)). Targeted mutations of the low affinity nerve growth factor receptor cause a disorder characterized by faulty sensory innovation of peripheral structures (Lee, K. F. et al., Cell 69:737 (1992)).
TNF and LT-α are capable of binding to two TNF receptors (the 55- and 75-kd TNF receptors). A large number of biological effects elicited by TNF and LT-α, acting through their receptors, include hemorrhagic necrosis of transplanted tumors, cytotoxicity, a role in endotoxic shock, inflammation, immunoregulation, proliferation and anti-viral responses, as well as protection against the deleterious effects of ionizing radiation. TNF and LT-α are involved in the pathogenesis of a wide range of diseases, including endotoxic shock, cerebral malaria, tumors, autoimmune disease, AIDS and graft-host rejection (Beutler, B. and Von Huffel, C., Science 264:667-668 (1994)). Mutations in the p55 Receptor cause increased susceptibility to microbial infection.
Moreover, an about 80 amino acid domain near the C-terminus of TNFR1 (p55) and Fas was reported as the “death domain,” which is responsible for transducing signals for programmed cell death (Tartaglia et al., Cell 74:845 (1993)).
Apoptosis, or programmed cell death, is a physiologic process essential to the normal development and homeostasis of multicellular organisms (H. Steller, Science 267, 1445-1449 (1995)). Derangements of apoptosis contribute to the pathogenesis of several human diseases including cancer, neurodegenerative disorders, and acquired immune deficiency syndrome (C. B. Thompson, Science 267, 1456-1462 (1995)). Recently, much attention has focused on the signal transduction and biological function of two cell surface death receptors, Fas/APO-1 and TNFR-1 (J. L. Cleveland, et al., Cell 81, 479-482 (1995); A. Fraser, et al., Cell 85, 781-784 (1996); S. Nagata, et al., Science 267, 1449-56 (1995)). Both are members of the TNF receptor family which also include TNFR-2, low affinity NGFR, CD40, and CD30, among others (C. A. Smith, et al., Science 248, 1019-23 (1990); M. Tewari, et al., in Modular Texts in Molecular and Cell Biology M. Purton, Heldin, Carl, Ed. (Chapman and Hall, London, 1995). While family members are defined by the presence of cysteine-rich repeats in their extracellular domains, Fas/APO-1 and TNFR-1 also share a region of intracellular homology, appropriately designated the “death domain”, which is distantly related to the Drosophila suicide gene, reaper (P. Golstein, et al., Cell 81, 185-6 (1995); K. White et al., Science 264, 677-83 (1994)). This shared death domain suggests that both receptors interact with a related set of signal transducing molecules that, until recently, remained unidentified. Activation of Fas/APO-1 recruits the death domain-containing adapter molecule FADD/MORT1 (A. M. Chinnaiyan, et al., Cell 81, 505-12 (1995); M. P. Boldin, et al., J. Biol Chem 270, 7795-8 (1995); F. C. Kischkel, et al., EMBO 14, 5579-5588 (1995)), which in turn binds and presumably activates FLICE/MACH1, a member of the ICE/CED-3 family of pro-apoptotic proteases (M. Muzio et al., Cell 85, 817-827 (1996); M. P. Boldin, et al, Cell 85, 803-815 (1996)). While the central role of Fas/APO-1 is to trigger cell death, TNFR-1 can signal an array of diverse biological activities-many of which, stem from its ability to activate NF-kB (L. A. Tartaglia, et al., Immunol Today 13, 151-3 (1992)). Accordingly, TNFR-1 recruits the multivalent adapter molecule TRADD, which like FADD, also contains a death domain (H. Hsu, et al., Cell 81, 495-504 (1995); H. Hsu, et al., Cell 84, 299-308 (1996)). Through its associations with a number of signaling molecules including FADD, TRAF2, and RIP, TRADD can signal both apoptosis and NF-kB activation (H. Hsu, et al., Cell 84, 299-308 (1996); H. Hsu, et al., Immunity 4, 387-396 (1996)).
One TNF-related apoptosis inducing ligand has been reported by several groups and has been ascribed the name Apoptosis Inducing Molecule I (AIM-I) (Intenation Application No. WO 97/33899) and TNF-related apoptosis-inducing ligand or (TRAIL) (Wiley, S. R. et al., Immunity 3:673-682 (1995)). Pitti, R. M. et al., refer to the new molecule as Apo-2 ligand or (“Apo-2L”). For convenience, it will be referred to herein as TRAIL. The amino acid sequence of TRAIL is given in SEQ ID NO:66.
Unlike FAS ligand whose transcripts appear to be largely restricted to stimulated T-cells, significant levels of TRAIL are seen in many tissues, and it is constitutively transcribed by some cell lines. It has been shown that TRAIL acts independently from FAS ligand (Wiley, S. R., et al. (1995)), supra). Studies by Marsters, S. A. et al., have indicated that TRAIL activates apoptosis rapidly, within a time frame that is similar to death signalling by FAS/Apo-1L but much faster than TNF-induced apoptosis (Current Biology, 6:750-752 (1996)).
As many as five TRAIL receptors have been identified, including TR4 (also known as TRAIL receptor 1 (TRAIL-R1) and death receptor 4 (DR4), Pan et al., Science 276:111-3 (1997), International Patent Application Nos. WO98/32856, WO00/67793, WO99/37684, WO2000/34355, WO99/02653, SEQ ID NO:1); TR7 (also referred to as TRAIL receptor 2 (TRAIL-R2), DR5, and KILLER, Pan et al., Science 277:815-8 (1997), Sheridan et al., Science 277:818-21 (1997), Chaudhury et al., Immunity 7:821-30 (1997), International Patent Application Nos. WO98/46643, WO99/09165, WO99/11791, WO98/41629, WO00/66156, and WO98/35986, SEQ ID NO:3); TR1 (also referred to as Osteoprotegrin (OPG) osteoclastogenesis inhibitory factor (OCIF), TNFRSF11B, and FTHMA-090 (International Patent Application Nos. WO98/12344, WO2000/54651, WO2001/04137, WO66/26217, WO98/07840, WO2000/21554, WO99/53942, and WO2001/03719, SEQ ID NO:5); TR5 (also referred to as TRAIL receptor 3 (TRAIL-R3), decoy receptor 1 (DcR1) and TRID) (Degli-Esposti et al., J. Exp. Med. 186:1165-70 (1997), International Patent Application Nos. WO98/30693, WO00/71150, WO99/00423, EP867509, WO98/58062, SEQ ID NO:2); and TR10 (also referred to as TRAIL Receptor 4 (TRAIL-R4), DcR2, and TRUNDD, Pan et al., FEBS Lett. 424:41-5 (1998), Degli-Eposti et al., Immunity 7:813-20 (1997), International Patent Application Nos. WO98/54202, WO00/73321, WO2000/08155, WO99/03992, WO 2000/34355 and WO9910484, SEQ ID NO:4). TR4 and TR7 contain death domains in their cytoplasmic tails and the triggering of these receptors results in apoptosis. On the other hand, TR1, TR5 and TR10 can inhibit apoptosis induced by the cytotoxic ligand TRAIL in part because of their absent or truncated cytoplasmic death domains, respectively. Each of the publications and patents cited above is hereby incorporated by reference in their entireties, particularly with respect to the nucleotide and amino acid sequences of the TRAIL receptors disclosed therein.
The effects of TNF family ligands and TNF family receptors are varied and influence numerous functions, both normal and abnormal, in the biological processes of the mammalian system. There is a clear need, therefore, for identification and characterization of compositions, such as antibodies, that influence the biological activity of TNF receptors, both normally and in disease states. In particular, there is a need to isolate and characterize antibodies that modulate the biological activities of TRAIL receptors.